Abstract

A new supramolecular sensitizer for nickel(II) ion in aqueous solution based on a pyridyltriazolopyridine-cyclodextrin inclusion complex is proposed. The inclusion complexation behavior, characterization and binding ability of pyridyltriazolopyridine (PTP) with dimethyl-beta-cyclodextrin (DM beta CD) has been investigated both in solution and solid state by means of absorption, fluorescence, H-1 NMR, DSC, and molecular modeling methods. The stoichiometry of the inclusion complex is 1:1, and the thermodynamic studies indicate that the inclusion of PTP is mainly an entropic driven process. The 2D NMR studies revealed that the pyridyl-triazolopyridine is included by both sides of cyclodextrin which are in good agreement with the docking results. The fluorescence changes upon addition of divalent cations to the inclusion complex indicate a high selectivity and sensitivity for Ni2+ by fluorescence quenching in neutral aqueous solution. (C) 2014 Elsevier Ltd. All rights reserved.